JP2004156693A

JP2004156693A - Diaphragm

Info

Publication number: JP2004156693A
Application number: JP2002322489A
Authority: JP
Inventors: Masaki Furuta; 雅樹古田; Shigeru Osugi; 滋大杉
Original assignee: CKD Corp
Current assignee: CKD Corp
Priority date: 2002-11-06
Filing date: 2002-11-06
Publication date: 2004-06-03
Anticipated expiration: 2022-11-06
Also published as: JP4221206B2

Abstract

<P>PROBLEM TO BE SOLVED: To provide a diaphragm capable of reducing deterioration caused by stress concentration at a thin film part, and improving durability of a diaphragm. <P>SOLUTION: The thin film part 3 is integrally formed with an outer circumference at a lower end of a valve element part 2 formed in a columnar form, and a thick circumferential edge part 4 is integrally formed with the outer circumference of the thin film part 3. The thin film part 3 is extended horizontally from the outer circumference at the lower end of the valve element part 2. A first part 3a protruded in an upward semi-circular form is connected to a second part 3b protruded in a downward semi-circular form through a third part 3b to make a gentle S-form. In accordance with valve opening/closing action of the valve element part 2, the first part 3a and the second part 3b are freely deformed, so that stress is dispersed to each part of the thin film part 3. <P>COPYRIGHT: (C)2004,JPO

Description

【０００１】
【発明の属する技術分野】
本発明は、一次側流路と二次側流路との境に設けられた弁座に対して当接又は離間されるダイアフラムに関するものである。
【０００２】
【従来の技術】
従来より、例えば、半導体製造工程では、腐食性の高い性質を持つ薬液の供給を制御弁で制御しており、制御弁は、薬液と金属との非接触状態を保つためにダイアフラム弁を内蔵している。図５は、ダイアフラム弁の断面図であって、閉弁状態を示している。図６は、ダイアフラム弁の断面図であって、開弁状態を示している。
【０００３】
ダイアフラム弁は、ボディ５１、ダイアフラム６０等で構成され、ボディ５１に設けた弁座５３にダイアフラム６０を当接又は離間させることにより、図示しない一次側流路と二次側流路５２とを開放又は遮断して、薬液の供給を制御している。ダイアフラム６０は、ＰＴＦＥやＰＦＡなどのプラスチックを削りだして形成したものであり、弁座５３に当接可能な円柱形状の弁体部６１を中心部に備えている。弁体部６１の上端面には、図示しない駆動手段により上下方向に往復運動するピストンロッド５４が連結され、下端面外周には、薄膜部６２が一体に形成されている。その薄膜部６２の外周には肉厚の周縁部６３が一体に形成され、ダイアフラム６０は、ボディ５１とシリンダ５０で周縁部６３を狭持されることにより、ボディ５１とシリンダ５０との間に形成される空間を気密に区画し、薬液と接する作動室５５と薬液と接しない背室５６とを形成している。
【０００４】
こうしたダイアフラム６０は、作動室５５に入力した薬液から図中上向きの流体圧を受圧面に受けるため、薄膜部６２が上向きに半円形の凸形状を呈するよう形成されている。図７は、図５に示すＧ部の拡大断面図である。
薄膜部６２は、受圧面が弁体部６１と周縁部６３との間に中心点Ｐ３を規定し、その中心点Ｐ３を中心として周縁部６３の内周面端部上を通過する半径ｒ３の円弧状（図中点線Ｃ３）に形成されるとともに、その円弧状の受圧面と弁体部６１の下端面外周とに接する接線方向に形成されており、断面が略Ｕ字形をなしている。そのため、薄膜部６２は、弁体部６１と周縁部６３に対してそれぞれ鋭角に接続し、薄膜部６２と弁体部６１との接続部分及び薄膜部６２と周縁部６３の接続部分に作用する流体圧による負荷を軽減することができる（例えば、特許文献１参照。）。
【０００５】
【特許文献１】
特開２００１−１５３２６１号公報（段落００３６、第１図。）
【０００６】
【発明が解決しようとする課題】
ところが、従来のダイアフラム６０には、以下の問題があった。
ダイアフラム６０は、開弁動作するときに、弁体部６１の外周面と薄膜部６２の背圧面とで形成される根本角を鋭角（図５参照）から略直角（図６参照）にまで広げるように変形するため、弁体部６１と薄膜部６２との接続部分において圧縮応力を受圧面に発生し、引張応力を背圧面に発生していた。そのため、ダイアフラム６０は、それらの引張応力や圧縮応力に対する剛性を確保するため、弁体部６１と薄膜部６２の接続部分を肉厚に形成しているが、肉厚が変化する部分は一般的に応力集中を生じやすく、薄膜部６２の一部（図中Ｔ参照）に応力集中に基づく劣化を発生する場合があった。
【０００７】
そこで、本発明は、上記課題を解決するためになされたものであり、薄膜部の応力集中に基づく劣化を減少させて、ダイアフラムの耐久性を向上させることができるダイアフラムを提供することを目的とする。
【０００８】
【課題を解決するための手段】
上記課題を解決するためになされた請求項１に記載の発明は、一次側流路と二次側流路との境に設けられた弁座に当接可能な円柱形状の弁体部と、弁体部の弁座と当接する端面外周に一体に形成された薄膜部と、薄膜部の外周に一体に形成された肉厚の周縁部とを備えるダイアフラムにおいて、薄膜部は、弁体部の外周面上に中心点を規定し、その中心点を中心として弁体部の弁座と当接する端面の外周に接する円弧状に受圧面を形成した第１の部位を有することを特徴とする。
【０００９】
すなわち、薄膜部が弁体部の弁座と当接する端面外周に対して略垂直に接続しており、弁体部が開弁動作するときには、第１部位を円弧状から平面状に伸ばすように撓ませ、その一方で、弁体部が閉弁動作するときには、第１部位を平面状から円弧状に復元させるため、開閉弁動作の前後で弁体部と薄膜部との接続状態が略垂直に維持されて殆ど変化しないので、弁体部と薄膜部との接続部分を肉厚にする必要がなく、薄膜部の応力集中に基づく劣化を減少させて、ダイアフラムの耐久性を向上させることができる。
【００１０】
また、請求項２に記載の発明は、請求項１に記載の発明において、薄膜部は、周縁部の内周面を弁体部が弁座に当接する方向に延長した延線上に中心点を規定し、その中心点を中心として周縁部の内周面端部に接する円弧状に受圧面を形成した第２の部位を有することを特徴とする。
【００１１】
すなわち、薄膜部が周縁部の内周面端部に対して略垂直に接続しており、第１の部位と同様に、弁体部が開弁動作するときには、第２の部位を円弧状から平面状に伸ばすように撓ませ、その一方で、弁体部が閉弁動作するときには、第２の部位を平面状から円弧状に復元させるため、開閉弁動作の前後で周縁部と薄膜部との接続状態が略垂直に維持されて殆ど変化しないので、薄膜部を周縁部に鋭角に接続させなくても、薄膜部と周縁部との接続部分で発生する応力を小さくすることができる。
【００１２】
また、請求項３に記載の発明は、請求項２に記載の発明において、薄膜部は、第１の部位の受圧面と第２の部位の受圧面とに接する接線方向に受圧面を形成した第３の部位を有することを特徴とする。
すなわち、薄膜部がＳ字形をなし、弁体部の開閉弁動作に従って第１の部位と第２の部位が自由に変形し、薄膜部全体が滑らかに変形するので、応力を薄膜部の各部に分散させることができる。
【００１３】
また、請求項４に記載の発明は、薬液を制御する制御弁に内蔵され、一次側流路と二次側流路との境に設けられた弁座に当接可能な円柱形状の弁体部と、弁体部の弁座と当接する端面外周に一体に形成された薄膜部と、薄膜部の外周に一体に形成された肉厚の周縁部とを備えるプラスチック製のダイアフラムにおいて、薄膜部は、弁体部の端面外周から水平方向に延設され、弁体部が弁座と当接する方向に半円形の凸形状を呈する第１の部位と、周縁部の内周面端部から水平方向に延設され、弁体部が弁座から離間する方向に半円形の凸形状を呈する第２の部位と、第１の部位と第２の部位とに直線的に接続する第３の部位とを有することを特徴とする。
【００１４】
すなわち、薄膜部が略Ｓ字形を描くように形成され、弁体部が開弁動作して薬液を供給するときには、薄膜部の第１の部位と第２の部位とが半円状から平面状に伸びるように撓み、その一方で、弁体部が閉弁動作して薬液を遮断するときには、薄膜部の第１の部位と第２の部位とが平面状から半円状に復元することにより薄膜部全体を滑らかに変形させ、応力を各部に分散させることにより、薬液に対するダイアフラムの耐久性を向上させることができる。
【００１５】
また、請求項５に記載する発明は、請求項１乃至請求項４の何れか１つに記載の発明において、第１の部位が第２の部位より小さく形成されていることを特徴とする。
すなわち、ダイアフラムは、周縁部を固定され、弁体部のみが弁座と当接又は離間する方向に往復運動するため、薄膜部は第１の部位、第３の部位、第２の部位の順に変形することとなるが、第１の部位を第２の部位より小さく形成したことにより、第１の部位と第２の部位とが変形する時間の差を短くすることができ、薄膜部を滑らかに変形させることができる。
【００１６】
また、請求項６に記載の発明は、請求項１乃至請求項５の何れか１つに記載の発明において、フッ素樹脂を材質とすることを特徴とする。
すなわち、ダイアフラムの耐薬液性を確保することができる。
【００１７】
【発明の実施の形態】
次に、本発明に係るダイアフラムの実施の形態について図面を参照して説明する。図１は、閉弁状態のダイアフラム弁の断面図である。図２は、開弁状態のダイアフラム弁の断面図である。
本実施の形態のダイアフラム１も、従来のダイアフラム６０と同様にダイアフラム弁に使用され、フッ酸等の薬液の供給を制御する制御弁に内蔵されている。ダイアフラム弁は、ボディ５１やダイアフラム１などを備え、ボディ５１は、ＰＴＦＥやＰＦＡなどのプラスチックで形成されている。ボディ５１には、図示しない一次側流路と二次側流路５２との境に弁座５３が設けられ、弁座５３の周囲に環状の周溝５７が形成されている。ダイアフラム１は、周溝５７に嵌め合わされた状態で外周をボディ５１とシリンダ５０とで狭持され、ボディ５１とシリンダ５０との間に形成された空間を気密に区画して、薬液が接触する作動室５５と薬液が接触しない背室５６とを形成している。
【００１８】
図３は、ダイアフラム１の断面図である。
ダイアフラム１は、ＰＴＦＥやＰＦＡ等のプラスチックを機械加工で削りだしたものであり、短い円柱形状の弁体部２の周りに薄膜部３と周縁部４とが同心円状に形成されている。弁体部２は、上端面にネジ孔２ａが形成され、図示しない駆動手段により上下方向に往復運動するピストンロッド５４（図１参照）と螺合して接続するようになっている。そして、弁体部２の下端面外周には、薄肉の薄膜部３が一体的に形成され、その薄膜部３の外周に肉厚の周縁部４が一体的に形成されている。周縁部４には、下方に伸びるシール部４ａが設けられ、そのシール部４ａをボディ５１の周溝５７（図１参照）に圧入することによりシール性を確保できるようになっている。
【００１９】
図４は、薄膜部３の拡大断面図である。
薄膜部３は、断面がゆるやかなＳ字形を描くように一定の膜厚Ａで形成されており、弁体部２と接続して下向きに半円形の凸形状を呈する第１の部位３ａと、周縁部４と接続して上向きに半円形の凸形状を呈する第２の部位３ｂと、第１の部位３ａと第２の部位３ｂとを接続する直線状の第３の部位３ｃとから構成されている。
【００２０】
第１の部位３ａは、弁体部２の外周面上に中心点Ｐ１を規定し、その中心点Ｐ１を中心として弁体部２の下端面外周に接する半径ｒ１の円弧状（図中点線Ｃ１）に受圧面を形成し、弁体部２の下端面外周に対して略垂直に接続している。また、第２の部位３ｂは、周縁部４の内周面を延長した延線Ｌ上に中心点Ｐ２を規定し、その中心点Ｐ２を中心として周縁部４の内周面の下端部に接する半径ｒ２の円弧状（図中点線Ｃ２）に受圧面を形成し、周縁部４の内周面の下端部に対して略垂直に接続している。さらに、第３の部位３ｃは、第１の部位３ａの受圧面と第２の部位３ｂの受圧面とに接する接線方向に受圧面を形成し、第１の部位３ａと第２の部位３ｂとを接続して一体化している。従って、ダイアフラム１は、弁体部２と薄膜部３との接続部分及び薄膜部３と周縁部４との接続部分などに凹凸がなく、受圧面が滑らかに形成されている。そして、第１の部位３ａの半径ｒ１は、第２の部位３ｂの半径ｒ２より小さく設定され、第１の部位３ａが第２の部位３ｂより小さく形成されている。
【００２１】
ここで、中心点Ｐ１，Ｐ２は、薄膜部３の断面が略Ｓ字形になるよう形成することを前提として、有限要素法による応力解析により制約条件の中で最も応力が小さくなるよう決定される。
【００２２】
このようなダイアフラム１は、ダイアフラム弁に組み付けられて以下のように動作する。
ピストンロッド５４が図示しない駆動手段により図中上向きに移動すると、図２に示すように、ダイアフラム１の弁体部２がピストンロッド５４に引き上げられて弁座５３から離間し、薬液を図示しない一次側流路から二次側流路５２に供給する。このとき、薄膜部３は、周縁部４が所定位置に固定されているため弁体部２の移動に従って変形し、弁体部２との接続部分を基点として第１の部位３ａが円弧状から平面状に伸ばされるように変形するとともに、周縁部４との接続部分を基点として第２の部位３ｂが円弧状から平面状に伸ばされるように変形する。
【００２３】
一方、ピストンロッド５４が図示しない駆動手段により図中下向きに移動すると、図１に示すように、ダイアフラム１の弁体部２がピストンロッド５４に押し下げられて弁座５３に当接し、薬液を図示しない一次側流路から二次側流路５２に供給しなくなる。このとき、薄膜部３は、周縁部４側端部が固定されているため弁体部２の移動に従って変形し、弁体部２との接続部分を基点として第１の部位３ａが平面状から円弧状に復元するとともに、周縁部４との接続部分を基点として第２の部位３ｂが平面上から円弧状に復元する。すなわち、薄膜部３全体が復元力で変形し、元の形状に復帰する。
【００２４】
尚、ダイアフラム１は、弁体部２が開弁動作したときに（図２参照）、同じく開弁状態のダイアフラム６０（図６参照）と同様に薄膜部３が撓むにもかかわらず（図１、図２参照）、その撓んだ部分で発生する応力が小さい。これは、ダイアフラム１は、撓んだ部分が予め湾曲した第２の部位３ｂに該当し、開閉弁動作の前後の変化量が小さいのに対して、ダイアフラム６０は、撓んだ部分が直線部分に該当するため、開閉閉弁動作の前後の変化量が大きくなるためであると考えられる。
【００２５】
従って、本実施の形態のダイアフラム１によれば、薄膜部３が弁体部２の下端面外周に対して略垂直に接続し、開閉弁動作の前後で弁体部２との接続状態が略垂直に維持されて殆ど変化しないので（図１、図２参照）、弁体部２と薄膜部３との接続部分を肉厚にする必要がなく、応力集中に基づく劣化を減少させて、耐久性を向上させることができる。
【００２６】
また、本実施の形態のダイアフラム１によれば、薄膜部３が、周縁部４の内周面の下端部に対して略垂直に接続し、開閉弁動作の前後で周縁部４との接続状態が略垂直に維持されて殆ど変化しないので（図１、図２参照）、従来のダイアフラム６０のように薄膜部６２を周縁部６３に対して鋭角に接続させなくても（図５、図６参照）、薄膜部３と周縁部４との接続する部分の応力を従来のダイアフラム６０と同程度に小さくすることができる。
【００２７】
また、本実施の形態のダイアフラム１によれば、薄膜部３がゆるやかなＳ字形をなし、弁体部２の開閉弁動作に従って薄膜部３全体が滑らかに変形するので、応力を薄膜部３の各部に分散させることができる。
【００２８】
また、上記実施の形態のダイアフラム１によれば、周縁部４を固定され、弁体部２のみが上方向に移動するため、薄膜部３は第１の部位３ａ、第３の部位３ｃ、第２の部位３ｂの順に変形することとなるが、第１の部位３ａを第２の部位３ｂより小さく形成したことにより、第１の部位３ａが変形する時間と第２の部位３ｂが変形する時間との差を短くすることができ、薄膜部３を滑らかに変形させることができる。
【００２９】
以上、本発明に係るダイアフラムの一実施の形態について説明したが、本発明はこれに限定されるわけではなく、その趣旨を逸脱しない範囲で様々な変更が可能である。
【００３０】
（１）上記実施の形態では、第１の部位３ａを第２の部位３ｂより小さく形成した。それに対して、動作回数が少なく耐圧性のみを考慮する場合や、作動流体の温度、圧力、流量等に基づいて、第１の部位３ａと第２の部位３ｂとを同じ大きさにしたり、第１の部位３ａと第２の部位３ｂより大きく形成してもよい。
【００３１】
（２）上記実施の形態では、中心点Ｐ１を弁体部２の外周面上に規定した。それに対して、中心点Ｐ１は、弁体部２の外周面端部に接する円弧Ｃ１を描けるものであればよく、弁体部２の外周面を延長した延線上に規定するようにしてもよい。また、上記実施の形態では、中心点Ｐ２を周縁部４の内周面を延長した延線Ｌ上に規定した。それに対して、中心点Ｐ２は、周縁部４の内周面端部に接する円弧Ｃ２を描けるものであればよく、周縁部４の内周面上に規定するようにしてもよい。
【００３２】
（３）上記実施の形態では、ダイアフラム１をＰＴＦＥやＰＦＡなどのプラスチックで形成した。それに対して、ダイアフラム１の材質をゴム等にしてもよい。
【００３３】
【発明の効果】
従って、本発明のダイアフラムによれば、一次側流路と二次側流路との境に設けられた弁座に当接可能な円柱形状の弁体部と、弁体部の弁座と当接する端面外周に一体に形成された薄膜部と、薄膜部の外周に一体に形成された肉厚の周縁部とを備えるダイアフラムにおいて、薄膜部は、弁体部の外周面上に中心点を規定し、その中心点を中心として弁体部の弁座と当接する端面の外周に接する円弧状に受圧面を形成した第１の部位を有しているので、弁体部と薄膜部との接続部分を肉厚にする必要がなく、薄膜部の応力集中に基づく劣化を減少させて、ダイアフラムの耐久性を向上させることができる。
【００３４】
また、本発明のダイアフラムによれば、薬液を制御する制御弁に内蔵され、一次側流路と二次側流路との境に設けられた弁座に当接可能な円柱形状の弁体部と、弁体部の弁座と当接する端面外周に一体に形成された薄膜部と、薄膜部の外周に一体に形成された肉厚の周縁部とを備えるプラスチック製のダイアフラムにおいて、薄膜部は、弁体部の端面外周から水平方向に延設され、弁体部が弁座と当接する方向に半円形の凸形状を呈する第１の部位と、周縁部の内周面端部から水平方向に延設され、弁体部が弁座から離間する方向に半円形の凸形状を呈する第２の部位と、第１の部位と第２の部位とに直線的に接続する第３の部位とを有しているので、薬液に対するダイアフラムの耐久性を向上させることができる。
【図面の簡単な説明】
【図１】本発明の実施の形態において、閉弁状態のダイアフラム弁の断面図である。
【図２】同じく、開弁状態のダイアフラム弁の断面図である。
【図３】同じく、ダイアフラムの断面図である。
【図４】同じく、薄膜部の拡大断面図である。
【図５】従来のダイアフラムを使用するダイアフラム弁の断面図であって、閉弁状態を示している。
【図６】従来のダイアフラムを使用するダイアフラム弁の断面図であって、開弁状態を示している。
【図７】図５に示すＧ部の拡大断面図である。
【符号の説明】
１ダイアフラム
２弁体部
３薄膜部
３ａ第１の部位
３ｂ第２の部位
３ｃ第３の部位
４周縁部
５２二次側流路
５３弁座
Ｌ延線
Ｐ１中心点
Ｐ２中心点[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a diaphragm that comes into contact with or separates from a valve seat provided at a boundary between a primary flow path and a secondary flow path.
[0002]
[Prior art]
Conventionally, for example, in a semiconductor manufacturing process, the supply of a highly corrosive chemical has been controlled by a control valve, and the control valve has a built-in diaphragm valve to maintain a non-contact state between the chemical and metal. ing. FIG. 5 is a cross-sectional view of the diaphragm valve, showing a closed state. FIG. 6 is a cross-sectional view of the diaphragm valve, showing an open state.
[0003]
The diaphragm valve is composed of a body 51, a diaphragm 60, and the like. The diaphragm 60 is brought into contact with or separated from a valve seat 53 provided on the body 51 to open a primary flow path and a secondary flow path 52 (not shown). Alternatively, the supply of the chemical is controlled by shutting off. The diaphragm 60 is formed by shaving a plastic such as PTFE or PFA, and has a cylindrical valve body 61 at the center which can abut the valve seat 53. A piston rod 54 that reciprocates in a vertical direction by a driving means (not shown) is connected to the upper end surface of the valve body portion 61, and a thin film portion 62 is integrally formed on the outer periphery of the lower end surface. A thick peripheral portion 63 is integrally formed on the outer periphery of the thin film portion 62, and the diaphragm 60 is sandwiched between the body 51 and the cylinder 50 by sandwiching the peripheral portion 63 between the body 51 and the cylinder 50. The formed space is air-tightly partitioned to form a working chamber 55 in contact with the chemical and a back chamber 56 not in contact with the chemical.
[0004]
The diaphragm 60 is formed such that the thin film portion 62 has a semicircular convex shape upward because the diaphragm 60 receives an upward fluid pressure in the figure from the chemical solution input to the working chamber 55 on the pressure receiving surface. FIG. 7 is an enlarged sectional view of a portion G shown in FIG.
The thin film portion 62 has a pressure receiving surface defining a center point P3 between the valve body portion 61 and the peripheral edge portion 63, and a radius r3 of a radius r3 passing over the inner peripheral end of the peripheral edge portion 63 around the center point P3. It is formed in an arc shape (dotted line C3 in the figure), and is formed in a tangential direction in contact with the arc-shaped pressure receiving surface and the outer periphery of the lower end surface of the valve body portion 61, and has a substantially U-shaped cross section. Therefore, the thin film portion 62 is connected to the valve portion 61 and the peripheral portion 63 at an acute angle, and acts on the connection portion between the thin film portion 62 and the valve portion 61 and the connection portion between the thin film portion 62 and the peripheral portion 63. The load due to the fluid pressure can be reduced (for example, see Patent Document 1).
[0005]
[Patent Document 1]
JP 2001-153261 A (paragraph 0036, FIG. 1).
[0006]
[Problems to be solved by the invention]
However, the conventional diaphragm 60 has the following problems.
When the diaphragm 60 performs the valve opening operation, the root angle formed by the outer peripheral surface of the valve body portion 61 and the back pressure surface of the thin film portion 62 increases from an acute angle (see FIG. 5) to a substantially right angle (see FIG. 6). Therefore, a compressive stress is generated on the pressure receiving surface and a tensile stress is generated on the back pressure surface at a connection portion between the valve body portion 61 and the thin film portion 62. For this reason, the diaphragm 60 has a thick connecting portion between the valve body portion 61 and the thin film portion 62 in order to secure the rigidity against the tensile stress and the compressive stress. In the thin film portion 62 (see T in the drawing) in some cases, the stress concentration may cause deterioration.
[0007]
Then, this invention is made in order to solve the said subject, It aims at providing the diaphragm which can reduce the deterioration based on the stress concentration of a thin film part, and can improve the durability of a diaphragm. I do.
[0008]
[Means for Solving the Problems]
The invention according to claim 1, which has been made to solve the above problem, has a cylindrical valve body portion that can abut a valve seat provided at a boundary between a primary flow path and a secondary flow path; In a diaphragm including a thin film portion integrally formed on the outer periphery of an end face of the valve body portion that comes into contact with a valve seat, and a thick peripheral portion integrally formed on the outer periphery of the thin film portion, the thin film portion is formed of the valve body portion. A center point is defined on the outer peripheral surface, and the first portion has a pressure receiving surface formed in an arc shape in contact with the outer periphery of an end surface that contacts the valve seat of the valve body with the center point as a center.
[0009]
That is, the thin film portion is connected substantially perpendicularly to the outer periphery of the end face that comes into contact with the valve seat of the valve body portion, and when the valve body portion performs the valve opening operation, the first portion is extended from the arc shape to the planar shape. On the other hand, when the valve body performs the valve closing operation, the first portion is restored from a planar shape to an arc shape, so that the connection state between the valve body and the thin film portion is substantially vertical before and after the opening and closing valve operation. It is not necessary to increase the thickness of the connecting portion between the valve body and the thin film part, and it is possible to reduce the deterioration due to the stress concentration of the thin film part and improve the durability of the diaphragm. it can.
[0010]
According to a second aspect of the present invention, in the first aspect of the present invention, the thin film portion has a center point on an extension extending from the inner peripheral surface of the peripheral portion in a direction in which the valve body portion comes into contact with the valve seat. It is characterized in that it has a second portion in which the pressure receiving surface is formed in an arc shape in contact with the inner peripheral end of the peripheral portion with the center point as a center.
[0011]
That is, the thin film portion is connected substantially perpendicularly to the end of the inner peripheral surface of the peripheral portion, and like the first portion, when the valve body portion performs the valve opening operation, the second portion is changed from an arc shape. In order to restore the second portion from a planar shape to an arc shape when the valve body portion performs the valve closing operation, the peripheral portion and the thin film portion before and after the opening and closing valve operation are bent when the valve body portion performs the valve closing operation. Since the connection state is maintained almost perpendicularly and hardly changes, the stress generated at the connection portion between the thin film portion and the peripheral portion can be reduced without connecting the thin film portion to the peripheral portion at an acute angle.
[0012]
According to a third aspect of the present invention, in the second aspect, the thin film portion has a pressure receiving surface formed in a tangential direction in contact with the pressure receiving surface of the first portion and the pressure receiving surface of the second portion. It has a third portion.
That is, since the thin film portion has an S shape and the first portion and the second portion are freely deformed according to the opening / closing operation of the valve body portion, and the entire thin film portion is smoothly deformed, stress is applied to each portion of the thin film portion. Can be dispersed.
[0013]
According to a fourth aspect of the present invention, there is provided a cylindrical valve body which is built in a control valve for controlling a chemical liquid and can contact a valve seat provided at a boundary between a primary flow path and a secondary flow path. Part, a thin film portion integrally formed on the outer periphery of an end face that comes into contact with the valve seat of the valve body, and a thick diaphragm formed integrally on the outer periphery of the thin film portion. The first portion extends in a horizontal direction from the outer periphery of the end surface of the valve body portion, and has a semicircular convex shape in a direction in which the valve body portion comes into contact with the valve seat; A second portion extending in the direction, and having a semicircular convex shape in a direction in which the valve body portion is separated from the valve seat, and a third portion linearly connected to the first portion and the second portion. And characterized in that:
[0014]
That is, when the thin film portion is formed so as to draw a substantially S-shape, and the valve body portion performs the valve opening operation to supply the chemical, the first portion and the second portion of the thin film portion are formed in a semicircular to planar shape. When the valve body closes and shuts off the chemical solution, the first and second portions of the thin film portion are restored from a planar shape to a semicircular shape. By smoothly deforming the entire thin film portion and dispersing the stress in each portion, the durability of the diaphragm with respect to the chemical solution can be improved.
[0015]
According to a fifth aspect of the present invention, in any one of the first to fourth aspects of the present invention, the first portion is formed smaller than the second portion.
That is, since the diaphragm has its peripheral edge fixed and only the valve body reciprocates in the direction in which it comes into contact with or separates from the valve seat, the thin film portion has the first portion, the third portion, and the second portion in this order. Although the first portion is deformed, the first portion is formed smaller than the second portion, so that the time difference between the first portion and the second portion can be reduced, and the thin film portion can be smoothed. Can be transformed into
[0016]
The invention according to claim 6 is the invention according to any one of claims 1 to 5, characterized in that the material is made of a fluororesin.
That is, the chemical resistance of the diaphragm can be ensured.
[0017]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, an embodiment of a diaphragm according to the present invention will be described with reference to the drawings. FIG. 1 is a sectional view of the diaphragm valve in a closed state. FIG. 2 is a sectional view of the diaphragm valve in an open state.
The diaphragm 1 of the present embodiment is also used for a diaphragm valve similarly to the conventional diaphragm 60, and is built in a control valve for controlling the supply of a chemical such as hydrofluoric acid. The diaphragm valve includes a body 51, the diaphragm 1, and the like, and the body 51 is formed of a plastic such as PTFE or PFA. In the body 51, a valve seat 53 is provided at a boundary between a primary flow path and a secondary flow path 52 (not shown), and an annular peripheral groove 57 is formed around the valve seat 53. The diaphragm 1 is clamped on its outer periphery by the body 51 and the cylinder 50 in a state of being fitted into the peripheral groove 57, airtightly partitions a space formed between the body 51 and the cylinder 50, and comes into contact with a chemical solution. A working chamber 55 and a back chamber 56 with which the chemical solution does not contact are formed.
[0018]
FIG. 3 is a sectional view of the diaphragm 1.
The diaphragm 1 is made by shaving a plastic such as PTFE or PFA by machining, and a thin film portion 3 and a peripheral edge portion 4 are formed concentrically around a short cylindrical valve body portion 2. The valve body portion 2 has a screw hole 2a formed in the upper end surface, and is screwed and connected to a piston rod 54 (see FIG. 1) which reciprocates in a vertical direction by a driving means (not shown). A thin thin film portion 3 is integrally formed on the outer periphery of the lower end surface of the valve body portion 2, and a thick peripheral portion 4 is integrally formed on the outer periphery of the thin film portion 3. The peripheral portion 4 is provided with a seal portion 4a extending downward, and the sealability can be secured by press-fitting the seal portion 4a into a peripheral groove 57 (see FIG. 1) of the body 51.
[0019]
FIG. 4 is an enlarged cross-sectional view of the thin film section 3.
The thin film portion 3 is formed with a constant film thickness A so as to draw a gentle S-shaped cross section, and is connected to the valve body portion 2 and has a first portion 3a having a downwardly semicircular convex shape, A second portion 3b connected to the peripheral portion 4 and having an upwardly semicircular convex shape, and a straight third portion 3c connecting the first portion 3a and the second portion 3b. ing.
[0020]
The first portion 3a defines a center point P1 on the outer peripheral surface of the valve body portion 2 and has an arc shape with a radius r1 that is in contact with the outer periphery of the lower end surface of the valve body portion 2 around the center point P1 (dotted line C1 in the figure). ), A pressure receiving surface is formed, and is connected substantially perpendicularly to the outer periphery of the lower end surface of the valve body 2. In addition, the second portion 3b defines a center point P2 on an extension L extending the inner peripheral surface of the peripheral portion 4, and contacts the lower end of the inner peripheral surface of the peripheral portion 4 with the center point P2 as the center. A pressure receiving surface is formed in an arc shape with a radius r2 (dotted line C2 in the figure), and is connected substantially perpendicularly to the lower end of the inner peripheral surface of the peripheral portion 4. Further, the third portion 3c forms a pressure receiving surface in a tangential direction in contact with the pressure receiving surface of the first portion 3a and the pressure receiving surface of the second portion 3b, and the first portion 3a and the second portion 3b Are connected and integrated. Therefore, the diaphragm 1 has no unevenness in the connection portion between the valve body portion 2 and the thin film portion 3 and the connection portion between the thin film portion 3 and the peripheral edge portion 4, and the pressure receiving surface is formed smoothly. The radius r1 of the first portion 3a is set smaller than the radius r2 of the second portion 3b, and the first portion 3a is formed smaller than the second portion 3b.
[0021]
Here, the center points P1 and P2 are determined such that the stress is minimized by the finite element method stress analysis, assuming that the cross section of the thin film portion 3 is formed to be substantially S-shaped. .
[0022]
Such a diaphragm 1 is mounted on a diaphragm valve and operates as follows.
When the piston rod 54 moves upward in the figure by a driving means (not shown), the valve body 2 of the diaphragm 1 is pulled up by the piston rod 54 and separated from the valve seat 53 as shown in FIG. It is supplied from the side channel to the secondary side channel 52. At this time, since the peripheral portion 4 is fixed at a predetermined position, the thin film portion 3 is deformed according to the movement of the valve body portion 2, and the first portion 3 a is changed from an arc shape with the connection point with the valve body portion 2 as a base point. The second portion 3b is deformed so as to be extended from a circular arc shape to a planar shape with the connecting portion with the peripheral portion 4 as a base point.
[0023]
On the other hand, when the piston rod 54 moves downward in the figure by a driving means (not shown), as shown in FIG. 1, the valve body 2 of the diaphragm 1 is pushed down by the piston rod 54 and comes into contact with the valve seat 53, and the chemical solution is drawn. No supply from the primary flow path to the secondary flow path 52 is stopped. At this time, the thin film portion 3 is deformed in accordance with the movement of the valve body portion 2 because the end portion on the peripheral edge portion 4 side is fixed, and the first portion 3a is changed from a planar shape with the connection point with the valve body portion 2 as a base point. While being restored to an arc shape, the second portion 3b is restored to an arc shape from a plane with the connection point with the peripheral portion 4 as a base point. That is, the entire thin film portion 3 is deformed by the restoring force and returns to the original shape.
[0024]
When the valve body 2 performs the valve opening operation (see FIG. 2), the diaphragm 1 is bent in the same manner as the diaphragm 60 (see FIG. 6) in the valve open state (see FIG. 6). 1, see FIG. 2), the stress generated at the bent portion is small. This is because the diaphragm 1 corresponds to the second portion 3b in which the bent portion is curved in advance, and the amount of change before and after the opening / closing valve operation is small, whereas the diaphragm 60 has the bent portion in the linear portion. It is considered that the amount of change before and after the opening / closing valve closing operation is large.
[0025]
Therefore, according to the diaphragm 1 of the present embodiment, the thin film portion 3 is connected substantially perpendicularly to the outer periphery of the lower end surface of the valve body portion 2, and the connection state with the valve body portion 2 before and after the opening / closing operation is substantially reduced. Since it is maintained vertically and hardly changes (see FIGS. 1 and 2), it is not necessary to increase the thickness of the connection portion between the valve body portion 2 and the thin film portion 3, and it is possible to reduce deterioration due to stress concentration and to improve durability. Performance can be improved.
[0026]
Further, according to the diaphragm 1 of the present embodiment, the thin film portion 3 is connected substantially perpendicularly to the lower end of the inner peripheral surface of the peripheral portion 4, and the connection state with the peripheral portion 4 before and after the opening / closing valve operation. Is maintained substantially perpendicularly and hardly changes (see FIGS. 1 and 2), so that the thin film portion 62 does not need to be connected to the peripheral portion 63 at an acute angle unlike the conventional diaphragm 60 (FIGS. 5 and 6). ), The stress at the portion where the thin film portion 3 and the peripheral edge portion 4 are connected can be reduced to the same degree as that of the conventional diaphragm 60.
[0027]
Further, according to the diaphragm 1 of the present embodiment, the thin film portion 3 has a gentle S-shape and the entire thin film portion 3 is smoothly deformed according to the opening / closing operation of the valve body portion 2. It can be dispersed in each part.
[0028]
Further, according to the diaphragm 1 of the above embodiment, since the peripheral portion 4 is fixed and only the valve body 2 moves upward, the thin film portion 3 includes the first portion 3a, the third portion 3c, and the Although the second part 3b is deformed in the order, the first part 3a is formed smaller than the second part 3b, so that the first part 3a is deformed and the second part 3b is deformed. Can be shortened, and the thin film portion 3 can be smoothly deformed.
[0029]
As described above, one embodiment of the diaphragm according to the present invention has been described, but the present invention is not limited to this, and various changes can be made without departing from the gist of the present invention.
[0030]
(1) In the above embodiment, the first portion 3a is formed smaller than the second portion 3b. On the other hand, when the number of operations is small and only the pressure resistance is taken into consideration, or based on the temperature, pressure, flow rate, etc. of the working fluid, the first portion 3a and the second portion 3b may have the same size, It may be formed larger than the first portion 3a and the second portion 3b.
[0031]
(2) In the above embodiment, the center point P1 is defined on the outer peripheral surface of the valve body 2. On the other hand, the center point P1 may be any point as long as it can draw an arc C1 that is in contact with the end of the outer peripheral surface of the valve body 2, and may be defined on an extended line extending the outer peripheral surface of the valve body 2. . In the above embodiment, the center point P2 is defined on the extension L extending from the inner peripheral surface of the peripheral portion 4. On the other hand, the center point P2 may be any point as long as it can draw an arc C2 in contact with the end of the inner peripheral surface of the peripheral portion 4, and may be defined on the inner peripheral surface of the peripheral portion 4.
[0032]
(3) In the above embodiment, the diaphragm 1 is formed of a plastic such as PTFE or PFA. On the other hand, the material of the diaphragm 1 may be rubber or the like.
[0033]
【The invention's effect】
Therefore, according to the diaphragm of the present invention, a cylindrical valve body that can abut on a valve seat provided at the boundary between the primary side flow path and the secondary side flow path, and the valve seat of the valve body part are in contact with each other. In a diaphragm having a thin film portion integrally formed on the outer periphery of the contacting end surface and a thicker peripheral portion integrally formed on the outer periphery of the thin film portion, the thin film portion defines a center point on the outer peripheral surface of the valve body portion. And the first portion having the arc-shaped pressure receiving surface in contact with the outer periphery of the end surface that comes into contact with the valve seat of the valve body with the center point as the center. It is not necessary to increase the thickness of the portion, and it is possible to reduce the deterioration due to the stress concentration of the thin film portion and improve the durability of the diaphragm.
[0034]
Further, according to the diaphragm of the present invention, a cylindrical valve body portion which is built in the control valve for controlling the chemical liquid and can contact a valve seat provided at a boundary between the primary flow path and the secondary flow path. In a plastic diaphragm including a thin film portion integrally formed on an outer periphery of an end surface of the valve body portion that comes into contact with a valve seat, and a thick peripheral portion integrally formed on an outer periphery of the thin film portion, the thin film portion is A first portion extending in a horizontal direction from an outer periphery of an end surface of the valve body portion and having a semicircular convex shape in a direction in which the valve body portion comes into contact with the valve seat; A second portion extending in a direction in which the valve element portion is separated from the valve seat and having a semicircular convex shape, and a third portion linearly connected to the first and second portions. Therefore, the durability of the diaphragm with respect to the chemical solution can be improved.
[Brief description of the drawings]
FIG. 1 is a sectional view of a diaphragm valve in a closed state in an embodiment of the present invention.
FIG. 2 is a cross-sectional view of the diaphragm valve in an open state.
FIG. 3 is a sectional view of the diaphragm.
FIG. 4 is an enlarged sectional view of a thin film portion.
FIG. 5 is a cross-sectional view of a conventional diaphragm valve using a diaphragm, showing a closed state.
FIG. 6 is a cross-sectional view of a diaphragm valve using a conventional diaphragm, showing an open state.
FIG. 7 is an enlarged sectional view of a portion G shown in FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Diaphragm 2 Valve part 3 Thin film part 3a First part 3b Second part 3c Third part 4 Peripheral part 52 Secondary flow path 53 Valve seat L Extension line P1 Center point P2 Center point

Claims

A cylindrical valve body portion that can abut on a valve seat provided at a boundary between the primary side flow passage and the secondary side flow passage, and is integrally formed on an outer periphery of an end surface of the valve body portion that comes into contact with the valve seat. A thin film portion, and a diaphragm having a thick peripheral portion integrally formed on the outer periphery of the thin film portion,
The thin film portion defines a center point on the outer peripheral surface of the valve body portion, and forms a pressure receiving surface in an arc shape in contact with the outer periphery of an end surface of the valve body portion that comes into contact with the valve seat with the center point as a center. A diaphragm having a first portion.

The diaphragm according to claim 1,
The thin film portion defines a center point on an extension of the inner peripheral surface of the peripheral portion in a direction in which the valve body portion contacts the valve seat, and the inner peripheral surface of the peripheral portion with the center point as a center. A diaphragm having a second portion having a pressure receiving surface formed in an arc shape in contact with an end.

In the diaphragm according to claim 2,
The diaphragm, wherein the thin film portion has a third portion having a pressure receiving surface formed in a tangential direction in contact with the pressure receiving surface of the first portion and the pressure receiving surface of the second portion.

A cylindrical valve body that is built into a control valve that controls a chemical solution and that can contact a valve seat provided at a boundary between a primary flow path and a secondary flow path, and the valve seat of the valve body part In a plastic diaphragm comprising a thin film portion integrally formed on the outer periphery of the end face in contact with, and a thick peripheral portion formed integrally on the outer periphery of the thin film portion,
The thin film portion,
A first portion extending in a horizontal direction from an outer periphery of an end surface of the valve body, and having a semicircular convex shape in a direction in which the valve body contacts the valve seat;
A second portion extending in a horizontal direction from an end of an inner peripheral surface of the peripheral portion, and having a semicircular convex shape in a direction in which the valve body is separated from the valve seat;
A diaphragm having a third portion linearly connected to the first portion and the second portion.

In the diaphragm according to any one of claims 1 to 4,
The diaphragm wherein the first portion is formed smaller than the second portion.

In the diaphragm according to any one of claims 1 to 5,
A diaphragm made of fluororesin.